An octopus is a soft-bodied, eight-limbed mollusc of the order Octopoda. The order consists of some 300 species and is grouped within the class Cephalopoda with squids, cuttlefish, and nautiloids. Like other cephalopods, an octopus is bilaterally symmetric with two eyes and a beaked mouth at the center point of the eight limbs. The soft body can radically alter its shape, enabling octopuses to squeeze through small gaps. They trail their eight appendages behind them as they swim. The siphon is used both for respiration and for locomotion, by expelling a jet of water. Octopuses have a complex nervous system and excellent sight, and are among the most intelligent and behaviourally diverse of all invertebrates.
The Bolitaeninae are a subfamily, in the family Amphitretidae, of small, common pelagic octopuses found in all tropical and temperate oceans of the world. The taxonomy of this taxon is not entirely certain; recent research suggests just two genera exist, Bolitaena and Japetella, both of which are thought to be monotypic by some authorities and under this view, the family would represent two very similar species: Bolitaena pygmaea and Japetella diaphana. However, currently a second species of Bolitaena, B. massyae is also recognised.
Enteroctopus is an octopus genus whose members are sometimes known as giant octopus.
Metasepia pfefferi, also known as the flamboyant cuttlefish, is a species of cuttlefish occurring in tropical Indo-Pacific waters off northern Australia, southern New Guinea, as well as numerous islands of the Philippines, Indonesia and Malaysia. The flesh of this colorful cephalopod contains unique acids, making it unsuitable for consumption.
Eledone is a genus of octopuses forming the only genus in the family Eledonidae. It is mainly distributed in the northern and southern Atlantic Ocean, with one species, E. palari, described from the southwestern Pacific Ocean and eastern Indian Ocean in waters around Indonesia and Australia and another, E. microsicya, from the western Indian Ocean. One species, E. thysanophora, is now regarded as a synonym of the brush-tipped octopus.
Velodona togata is a species of octopus in the monotypic genus Velodona. First described by Carl Chun in 1915, with a second subspecies discovered by Guy Coburn Robson in 1924, it was named for the distinctive membranes on its arms.
Macroctopus maorum is known more commonly as the Maori octopus or the New Zealand octopus. They can also be known as Pinnoctopus cordiformis, is found in the waters around New Zealand and southern Australia. M. maorum is one of the largest and most aggressive octopus species living in the New Zealand and Australian waters. They feed mainly on crustaceans and fish. Although they have a short life span, the females lay thousands of eggs and are very protective of them.
Stauroteuthis syrtensis, also known as the glowing sucker octopus or bioluminescent octopus, is a species of small pelagic octopus found at great depths in the north Atlantic Ocean. It is one of a very small number of octopuses to exhibit bioluminescence.
The curled octopus, also known as the horned octopus, lesser octopus or northern octopus, is a species of cephalopod found in the northeast Atlantic, ranging from Norway to the Mediterranean, including the British Isles. It is of minor importance to fisheries, being mainly bycatch in the north eastern Atlantic and in the Mediterranean where the common octopus is the preferred catch.
Eledone massyae, the combed octopus, is a small benthic octopus found off the Atlantic coasts of southern South America, particularly Argentina and southern Brazil.
Sepia elegans, the elegant cuttlefish, is a species of cuttlefish in the family Sepiidae from the eastern Atlantic Ocean and the Mediterranean Sea. It is an important species for fisheries in some parts of the Mediterranean where its population may have suffered from overfishing.
Sasakiopus is a genus of octopus containing only one species, Sasakiopus salebrosus, the rough octopus. It is part of the family Enteroctopodidae. Genetic analysis appeared to show that S. salebrosus is the sister taxon of the genera Benthoctopus and Vulcanoctopus, although the former is now considered a synonym of Bathypolypus, the only genus in the family Bathypolypodidae, and the latter as a synonym of Muusoctopus.
Macrochlaena winckworthi, Winckworth's octopus, is a little known species of octopus, it is the only species in the monotypic genus Macrochlaena, in the family Octopodidae. It was described by the British malacologist Guy Coburn Robson in 1926, the type specimens having been collected in the Gulf of Mannar, off Thoothukudi in Tamil Nadu, southeastern India.
Paroctopus is a small genus of octopuses from the family Octopodidae.
Wunderpus photogenicus, the wunderpus octopus, is a small-bodied species of octopus with distinct white and rusty brown coloration. 'Wunderpus' from German “wunder” meaning ‘marvel or wonder’.
Opisthoteuthis calypso is a species of genus Opisthoteuthis, which are known as the cirrate octopuses. Octopuses in this genus are known as the flapjack octopuses and can be found in a variety of oceans across the world.
Octopus insularis is a species of octopus described in 2008 from individuals found off the coast of Brazil, with a potentially much larger range.
Opisthoteuthis agassizii is a lesser-known, deep-sea octopus first described in 1883 by Addison E. Verrill.
Opisthoteuthis grimaldii is an octopus found near the Azores.
Opisthoteuths massyae is an octopus living in the eastern Atlantic Ocean.
